I have recently been seeing an issue with terrain after placing roads/scenery/buildings. The issue is as follows:
I will place the the abovementioned items down on flat terrain with no issue and continue playing with no issue. However, after saving the game, exiting, and eventually loading back in, terrain in some areas becomes heavily manipulated with sharp inclines/declines where I had placed a road or scenery items or buildings; drastically changing the landscape and shoving some scenery items beneath the ground.
Edit: The issue may be connected to the “Add Block” feature and how it registers “after-the-fact” with terrain/nearby structures and scenery